Along the River Murray Valley in South Australia (Fig. 5.1),
irrigation activities have resulted in several types of
environmental disruption which, while not directly life
threatening, have caused reduced livelihood levels and/or change
in the livelihood of farmers through deterioration of soil
quality. In addition, because of the steadily increasing salinity
gradient downstream, irrigators in the lower reaches of the river
have been forced to use water of undesirably high salinity. There
has been considerable damage to crops and orchards in irrigated
areas during periods of high salinity. Highly saline water piped
from Mannum to Adelaide (the capital city of South Australia) for
domestic consumption has caused serious problems for industry and
has affected domestic gardens. In the sense of the definition
above, salinization can certainly be seen as contributing to the
process of desertification in South Australia.

This paper is concerned with the human dimensions of the
salinization problem in South Australia. The perception of the
problem and of the range of alternatives available for the
management of the problem is investigated by questionnaire survey
of irrigation farmers along the Murray in South Australia, of
Adelaide residents, and also of relevant government officials.
The study highlights human perception as a critical variable in
the desertification process. It also suggests that success in the
battle against desertification can only be gained by altering
perception through effective education.

The Murray Valley in South Australia

South Australia is the driest state in Australia and Australia
is the driest continent in the world. Only 3 per cent of the
state receives an annual rainfall over 500 mm (20 inches) while
83 per cent gets less than 250 mm (10 inches). The River Murray
in South Australia is 700 km long but is the state's only major
river, and a large part of South Australia relies on it wholly or
partly for its water supply. Metropolitan Adelaide, the
Mid-North, upper Yorke Peninsula, the industrial cities at the
head of Spencer's Gulf, the upper South-East, and domestic and
stock users along the river are all supplied wholly or partly
from the Murray. Irrigators along the Murray Valley are totally
dependent upon the river for irrigation water used on vines,
trees, pastures, and vegetables. In all, the river supplies about
66 per cent of the state's consumption in an average season, but
this can rise to approximately 83 per cent in a dry season
(Engineering and Water Supply Department 1977a).

The River Murray in South Australia is 700 km long (Fig. 5.1).
The Murray Basin in South Australia is underlain by a
considerable thickness of Tertiary marine limestone, which in
turn is capped by fresh-water riverine and lacustrine deposits
which may reach 60 metres in thickness. The surface
characteristics of the basin are strongly related to a series of
Pleistocene and Recent aeolian deposits laid down as a series of
east-west sand dunes. These sand dunes represent the
rearrangement by prevailing westerly winds of littoral deposits
left by the retreating sea in Tertiary times (Sprigg 1952). This
sand dune country on both sides of the river valley from the
Victorian border to Murray Bridge is known as the Murray Mallee
and takes its name from the eucalypt vegetation known as mallee .
Much of this mallee vegetation has been cleared for agricultural
purposes (see chapter 4), but remnants of it remain along
roadsides and on some of the larger dunes.

Along much of its course in South Australia, the River Murray
is incised into the underlying Tertiary limestone, producing
vertical cliffs. The area available for intensive agricultural
development is restricted to relatively narrow alluvial flats on
the insides of meander bends or in the loops of abandoned
meanders. The other alternative is to irrigate the sandy mallee
soils at the top of the cliffs. Of the 35,000 ha of irrigation
along the River Murray in South Australia, 10,000 ha are within
the valley itself, and the remaining 25,000 ha are on the
highland soils adjacent to the river valley (Cole 1977).

Cole (1977) divides the Murray Valley Proper in South
Australia into three tracts (Fig. 5.1). Tract 1 consists of the
swamps, once permanently flooded, which occupy the first 90 km of
the river valley upstream from the mouth. Tract 2 is defined as
the predominantly low terrace soils of the narrow river valley
upstream from the swamps to Overland Corner. Tract 3 is composed
of the high and low terrace soils of the river valley from
Overland Corner to the Victorian border.

The heavy clay soils of the reclaimed swamps of Tract 1 are
high in organic matter, and while the level of irrigation
management is low, they have remained productive through 80 years
of irrigation. The low terrace soils of Tract 2 are saline gray
clays with poor physical properties and are subject to flooding.
Consequently, agricultural use is limited. In Tract 3 about 15
per cent of the area is high terrace, having clay soils with sand
layers at depth and at the surface. The horticultural areas of
Renmark, Cobdogla, and Berri are established here.

The higher mallee soils at the top of the cliffs are
characterized by some variability as both salt and clay have been
redistributed during wetter climatic periods. There was a
movement of salt and clay particles out of the higher parts of
the ridges and a corresponding accumulation in the lower troughs
(Gutteridge, Haskins, and Davey 1970, 14). The general pattern
for these higher ridges, then, is for sandy, well-drained ridges
alternating with saline, clayey depressions.

The groundwaters are generally highly saline in the area
through which the River Murray passes in South Australia.
Salinities are often higher than the salinity of seawater. The
regional groundwater trend is towards the river through aquifers
of medium transmissibility, notably the Loxton Parilla-Diapur
sands and the Morgan and Mannum limestones, and the deep incision
of the river allows considerable inflow.

The Settlement Process

Aboriginal people lived along the River Murray for over 30,000
years. They lived in harmony with their environment and did not
put any undue pressure on the hydrologic system.

Over the last 150 years western man has made increasing
demands on the river and has considerably altered both the
hydrological and ecological systems.

At first, in the absence of alternative modes of transport,
the River Murray was seen as an important avenue of trade, and
from 1850 to 1905 the river was plied by paddle steamers
transporting supplies to settlers and bringing wool and other
products to the ports. With the advent of competing railways,
navigation rapidly declined so that by the beginning of the
twentieth century, navigation was all but over.

After the very severe droughts of 1880 caused the abandonment
of large areas which had unwisely been taken up in the north of
the state, South Australians began to look for land which was
associated with a guaranteed water supply IWilliams 1974, 147).
This was at a time when irrigation was being actively talked
about, and this seemed to provide the answer. None of the rivers
and streams originating in South Australia were suitable for
large-scale irrigation projects, and so irrigation developments
have been concentrated along the River Murray.

In 1881 Governor Jervois reclaimed 3,300 acres (1,335 ha) of
swampland along the Murray near Wellington. This was followed by
a further reclamation of 650 acres 1263 ha) at Woods Point in
1882. Five years later an agreement was entered into between the
government of South Australia and the Chaffey brothers from
America for the establishment of private irrigation works near
Renmark.

During unemployment troubles in 1893, the government
authorized the formation of a number of village settlements, run
on community lines, and 11 of these were established in the Upper
Murray district (Tract 3 in Fig. 5.1). For a variety of reasons
most of these settlements failed. Lyrup settlement is the only
one remaining and is at present run on a cooperative system of
water supply with individual settlers having independent holdings
on perpetual lease. After 1896, most of the other settlements
were dissolved, or reorganized by the government. From then until
very recently almost all irrigation developments were government
sponsored. In 1908 a new settlement was established at Berri, and
first allotments were made in 1911, followed by Cobdogla in 1918.
In 1912, 2 of the village settlements, Waikerie and Ramco, were
incorporated as a Government Irrigation Area, and some years
later Holder was included.

The government reclaimed and subdivided more swamps along the
lower reaches of the Murray in 1904. Work commenced with the
Burdett and Mobilong areas and extended into other areas, so that
by 1929 most of the suitable swamplands between Mannum and
Wellington had been reclaimed and settled (Engineering and Water
Supply Department 1970, 2).

After World War I, Soldier Settlement areas were developed in
the Cobdogla, Waikerie, and Berri areas and in new areas at
Cadell, Chaffey, and Block "E" of Renmark. No further
government areas were developed for horticultural purposes until
after World War I I, when Loxton Irrigation Area and the Cooltong
Division of the Chaffey Area were developed as War Service Land
Settlement schemes.

In 1923, about 12 years after irrigation had been commenced in
the Berri and Moorook areas, it was found necessary to introduce
drainage schemes because of problems with waterlogging and
salinity. In the 1920s the whole Cadell Area was drained, and in
the 1930s and 1940s comprehensive drainage schemes were installed
in most areas. Many government irrigation areas are now supplied
with drainage, including Chaffey, Loxton, Berri, Cobdogla,
Moorook, and Cadell. Drainage schemes are also being installed in
the Renmark Irrigation Trust Area and the Lyrup Village District.

Irrigation Methods

Irrigation is confined to two main types, one involving high
lift pumping (Tracts 2 and 3 in Fig. 5.1), and the other gravity
flood irrigation in the reclaimed swamp areas in the lower
reaches. Due to the high valley sides it is not possible to
command large areas for irrigation by means of gravity channels
utilizing the natural fall of the river.

At a typical high lift irrigation settlement there is a main
pumping station, operated by electricity, on the bank of the
river. The water is lifted from the river to heights of 30 metres
or more and is run into the main channel, which may be 3 or 6
metres wide. From the main channel, subsidiary of "block
down" channels are given off.

The settlers' holdings in the older settlements usually
include 10 to 20 acres (4 to 8 ha) of water ratable land, but in
the newer settlements at Loxton, Cooltong, and Loveday they vary
from 20 to 30 acres (8 to 12 ha) with a few over 30 acres. There
is no limit to the area of land or the number of sections which
may be held, but that area of ratable land which one person may
hold is limited to 50 acres (20.2 ha).

The reticulation of the settlement is so arranged that a main
channel or pipeline is adjacent to each settler's holding, and at
irrigation periods each settler is given water by the opening of
appropriate channel gates, or valves, leading to the block down
channels for the stated number of hours allotted to him by the
irrigation authority. The usual watering period is four hours per
acre (ten hours per ha) based upon a flow of 2 feet (0.06 m3) per
second, which provides a 6 inch (15 cm) irrigation (Engineering
and Water Supply Department 1970, 2). The water irrigates the
fruit trees or vines by flowing along furrows prepared prior to
each irrigation. In some of the new settlements, the reticulation
in the settler's block is by pipes and the irrigation is by
overhead sprays, movable or fixed, with a tendency at present to
convert to under-tree sprinklers. Another recent development is a
move towards providing water on order rather than at fixed times.

In the reclaimed swamp areas (Tract 1 in Fig. 5.1) the
approach is different. Embankments keep the river from the
"swamps," and, when irrigation is required, sluice
gates in the embankments are opened to allow water to enter the
channels and gravitate throughout the area, each lessee
flood-irrigating his holding as water becomes available to him in
roster order.

The Salinity Problem

The process of salt accumulation in rivers of arid regions
from natural solutions of minerals and from irrigation processes
is the age-old nemesis of those peoples whose livelihood depends
upon irrigation in the arid zone. Man's ability to control
salinization of irrigated lands and to control salt concentration
downstream from irrigated areas has been tested from the
beginning of recorded history. There have been some successes and
many failures, and these are well documented by Eckholm (1975)
and Teclaff and Teclaff (1973). Irrigation in an arid region
involves a drastic change in hydrology, and, from the Tigris,
Euphrates, and Indus to the Rio Grande and Colorado, it has led
to increasing soil and river salinity. The situation with the
River Murray is no different.

The South Australian Engineering and Water Supply Department
recognizes the importance of the salinity problem:

Unquestionably, in terms of economic, environmental and social
cost, the major immediate threat to the River Murray is dissolved
salts, commonly referred to as salinity. [Engineering and
Water Supply Department 1977b, 3]

The recent River Murray Working Party Report (1975) also
highlights the salinity problem: "The Committee recognizes
that salinity is the major water pollution problem in the River
Murray."

The Size of the Problem

Generally the amount of salt passing through the river at any
time is constant at around 3,000 tonnes per day. Consequently,
during periods of high flow, the concentration of salinity is
less, and during periods of low flow the concentration is more.
So periods of low flow are the periods of most concern.

The World Health Organization accepts 830 EC units as the
maximum desirable for drinking water. It is also the level at
which overhead irrigated citrus suffers a 10 per cent loss of
yield (Engineering and Water Supply Department 1977b,3). At the
level of 1,250 EC units furrow and under tree irrigated citrus
suffers a 10 per cent loss, and overhead irrigated citrus suffers
permanent damage. For almost 20 per cent of the time since 1962
the salinity of the River Murray at Morgan has exceeded 850 EC
units, and on several occasions has exceeded 1,250 EC units. The
Engineering and Water Supply Department has admitted that if
agricultural losses are to be reduced, and if acceptable domestic
and industrial water is to be supplied, salinity in the Murray
must be reduced (Engineering and Water Supply Department 1977b,
4).

As the sea retreated from the Murray Basin in Tertiary times,
seawater was trapped in the underground sands and limestones.
From these vast underground reservoirs of salt, salinity finds
its way into the River Murray by three means: These are (1 )
natural inflow; (2) river structures; and (3) irrigation
drainage.

1. NATURAL INFLOW

Considerable salinity finds its way into the river by natural
drainage. This has been going on for thousands of years, and the
process is illustrated in Fig. 5.2. According to the Engineering
and Water Supply Department (1977b, 5). these inflows are of
particular concern in the lower reaches of the Murray and
particularly in South Australia because they are generally at a
greater rate and of higher concentration than upstream. Because
the underground salt reservoirs are enormous, this process will
continue for thousands of years to come.

2. RIVER STRUCTURES

Salinity is also increased by the locks and weirs along the
Murray. These structures were completed between 1922 and 1935 at
the insistence of the South Australian government, which was
determined to maintain the navigability of the river despite the
fact that the river trade had virtually disappeared by the turn
of the century. The locks and weirs increase river levels by
several metres. This causes increased pressure on underground
saline groundwater, forcing the salinity into the river
downstream as shown in Fig. 5.3.

3. IRRIGATION DRAINAGE

When land is irrigated it is normal for a proportion of the
water applied to drain through the soil and then find its way
into groundwater storages or nearby rivers. In the Murray Basin,
irrigation drainage seeps through the underground saline strata,
becomes increasingly saline, and then finds its way back into the
river. In the past, this problem has been partly tackled by
intercepting irrigation drainage in underground tile drains, and
then pumping it to evaporation basins on the river flats.
Unfortunately, seepage from these basins causes a return of high
salinity flows to the river. In addition, the capacity of the
basins is insufficient and occasional releases of saline water
are necessary. This again returns saline water to the river.
Irrigation drainage which is not intercepted and diverted to
evaporation basins eventually reaches the watertable. This builds
up what is called a "groundwater mound." This again
causes increased seepage of saline water to the river (Fig. 5.4).

Of the 1.1 million tonnes of salt which pass through the
Murray Mouth every year, 64 per cent derives from Victoria and
New South Wales (Engineering and Water Supply Department 1977b,
6). South Australia has no direct control over this.
Nevertheless, 400,000 tonnes of salt do enter the river in South
Australia. According to the estimates of the Engineering and
Water Supply Department (1977b, 6) this total comprises the
following:

Natural inflow: 130,000 tonnes per annum

River structures: 100,000 tonnes per annum

Irrigation drainage: 170,000 tonnes per annum

Solutions

The Engineering and Water Supply Department has made it clear
(1977b, 6) that whatever solutions are adopted, there can be only
relatively small reductions in River Murray salinity. This is
because a substantial proportion of inflow is simply not
controllable. For example, considerable natural inflow will
continue whatever action is taken. However, the negative impacts
of salinity can be significantly reduced by a small improvement
in present salinity levels. The salinity-to-impact relationship
is as shown in Fig. 5.5.

The Engineering and Water Supply Department is currently
investigating a range of options, which are discussed below.

POLITICAL ACTION

South Australia has no direct control over the actions of the
upstream states. The only way in which South Australia can
exercise any voice in matters such as upstream pollution is
through its representation on the River Murray Commission.
However, despite a recommendation of the River Murray Working
Party (1975) that the commission be given effective power over
the management of the quality of River Murray water, it remains
responsible only for quantity, and the states are continuing to
argue over the issue. The difficulties faced by South Australia
are highlighted by a statement by the New South Wales government
representative to the River Murray Working Party: "Water
pollution control in South Australia is regarded as a matter for
that state alone" (River Murray Working Party 1975, 9/11).
The South Australian Engineering and Water Supply Department
(1977b, 8) considers that all states should aim at significant
reductions in their salinity contributions to the river system.

UPGRADE EXISTING EVAPORATION BASINS

This proposal involves holding the drainage in basins when
river salinity is high, and then discharging the saline water
during high river flows. This proposal would have virtually no
effect on the mean annual river salinity, and
would be environmentally unacceptable because of the effects of
these basins on the flood-plain ecology. Cost is estimated at
$1.7 million (Engineering and Water Supply Department 1977c, 9).

DIRECT DISCHARGE TO THE RIVER

The suggestion here is to abandon all basins and remove them
from the floodplain. All drainage would then be discharged
directly into the river. The net effect of this would be an
increase in salinity and greater economic cost to the community.
There would, however, be environmental benefits at basin sites
through vegetation recovery. Cost is estimated at $1 million
(Engineering and Water Supply Department 1977c, 9).

SEGREGATED DISPOSAL

This proposal involves the use of basins only for high
salinity drainage. Low salinity drainage would be discharged
directly into the river. This would produce an overall reduction
in salinity of 5 per cent. Environmental conditions at
evaporation basins would improve, although they would still
remain on the floodplain. Cost is estimated at $2.7 million
(Engineering and Water Supply Department 1977c, 10).

NOORA BASIN

This proposal involves the establishment of a new basin at
Noora (20 km east of Loxton) to serve Renmark, Berri Barmera, and
Cobdogla. It is estimated that this would result in an overall
reduction of 15 per cent in average river salinities. The cost
would be between $16 million and $20 million (Engineering and
Water Supply Department 1977c, 11).

OCEAN DISPOSAL

This proposal involves the collection of all excess drainage
from the Upper Murray district and the pumping of the waste to
the ocean near the Murray mouth. This would result in an overall
reduction in mean river salinity of 16 per cent, but it would
cost approximately $90 million (Engineering and Water Supply
Department 1977c, 11).

NEW RIVER MURRAY WATERS AGREEMENT

This proposal involves building new River Murray Commission
storages and renegotiating the River Murray Waters Agreement to
increase dilution flows to South Australia. This would be an
effective solution, but it would involve the construction of a
major dam at a cost of approximately $120million.

SEPARATE SUPPLY

A supply channel or pipeline would be taken from Lake Victoria
so that the River Murray downstream from Lock 7 would then serve
as a drainage carrier. This would enable unrestricted discharge
of South Australian irrigation areas to the river, and
good-quality water would be received by the majority of
downstream users. There would, however, be severe environmental
damage associated with high salinities downstream from Lake
Victoria. The cost would be at least $200 million (Engineering
and Water Supply Department 1977c, 14).

WATER ON ORDER

In government irrigation areas, the roster system is being
replaced by the "water-on-order" method of supplying
irrigation water. Current investigations suggest that the
reduction in drainage run-off could be as high as 20 per cent
(Engineering and Water Supply Department 1977c, 14). This could
decrease saline seepage to the river in the long term, and
minimize the rate of growth of ground water mounds. Costs are
regarded as minimal.

IMPROVED IRRIGATION PRACTICES

This proposal involves the conversion of irrigation from
furrow to sprinklers, micro-jet, or drip. It is estimated that
conversion of 45 per cent of furrow in the Riverland (Tract 3 in
Fig. 5.1) could result in an overall reduction of 4 per cent in
average river salinities (Engineering and Water Supply Department
1977c, 14). Application rates would be lower and there would be
less seepage to the river. There would also be less effluent
reaching the evaporation basins. The average yield of some
irrigated crops would increase by 20 per cent to 30 per cent.
There is a need for the availability of low-interest loans to
encourage farmers to convert. Cost is estimated at approximately
$10 million.

LAND USE REDISTRIBUTION

One way of reducing drainage quantities is to reduce the
amount of irrigation in the Riverland. This could be achieved by
(a) property consolidation, (b) changing the types of crops
grown, (c) changing to dry-land farming, or (d) returning the
land to other uses. This could involve moving irrigated areas
farther from the river and the cessation altogether of irrigation
in some areas. The Industries Assistance Commission in its 1976
Report on the Riverland concluded that about 17 per cent of
Riverland farmers are economically non-viable. The commission
recommended assistance be given to cease irrigation in these
instances, and to find alternative occupations for these farmers.
This would result in a reduction of drainage effluent by 17
percent, and a reduction of river salinity on average by 3 per
cent. In addition, economic benefits would accrue to the
remaining irrigators. The cost of buying out and relocating 17
per cent of Riverland irrigators would be around $20 million and
would have to be implemented over a long period of time-say 20
years (Engineering and Water Supply Department 1977c, 16).

The Perception of Salinity

Throughout the world, the successes in controlling the
salinization of irrigated lands have come about through
scientific and technological advances. The failures have
generally resulted from man's inability to apply the knowledge
and processes available to him. Most scientific experts agree
that salinization need not get out of control in irrigated lands
if available management techniques are applied. This, however,
implies substantial capital investment, as well as the ability of
farmers and other decision-makers to accurately perceive both the
problem and the range of alternative solutions available to them.

A great deal of work has been done on people's perception of
life- or income-threatening environmental hazards, particularly
if of a catastrophic nature. Less attention has been directed at
topics relating to damage caused to man's activities by changes
in the environment occurring over an extended time span. Studies
which have been made of slowly occurring environmental
disruptions indicate not only a general lack of awareness of the
hazardous nature of these long-term effects, but ignorance of
their present existence (Rountree 1974). Environmental pollution
falls into this category, and salinity is certainly one form of
pollution.

A major finding from environmental cognition studies is the
sketchy and distorted information that most people have about the
cause and content of environmental pollution (David 1971;
Aulicems et a/. 1972; Wall 1973). Another important finding is
that there is a significant difference between the perception of
the lay public and that of technical managers in the area of
water resources management (Mitchell 1971, 139). Mitcheil's
research suggests that there are significant differences between
the perceptions of technical managers and the public, but not
between the perceptions of sub-groups of the public. It follows
from this that the opinion of the public should be consulted in
resource management situations. Another conclusion arrived at by
Mitchell (1971, 152) is that is is possible to generalize about
the public on cognitive, affective, and behavioural variables.

There has been very little research into the perception of
salinity specifically. Gindler and Holberts (1969, 389) have
suggested that, with the early appearance of salinity in the
Colorado River, it was not believed likely to increase. It was
commonly believed that silt would somehow blanket the salinity
and even reduce it. Dregne (1975, 49) has shown that attitudes
towards salinity control measures on the Colorado River fluctuate
with the amount of irrigation water available. When the flow of
the river is above normal, excess water is available for leaching
salts, and the salinity problem recedes. In dry years, the
opposite is true and pressures are generated to reduce irrigation
water salinity. Jackson (1977) administered a questionnaire to
farmers and non-farmers in Utah Valley, Utah, in order to
determine the level of awareness of environmental damage
associated with irrigation. The results of the survey revealed
that farmers seemed to be more concerned about the damages from
irrigation as determined by their voluntary responses to
open-ended questions about irrigation damage. One fourth of the
farmers indicated that they perceived some damage from
irrigation, but only 10 per cent of the non-farmers so responded.
When asked whether they were aware of specific damages, however,
three times as many non-farmers as farmers indicated awareness of
such damage as erosion, alkalinity, waterlogging, and so forth.
Farmer perception of damage increased only slightly when asked
about specific types. Both groups displayed a level of awareness
lower than anticipated. Livermore (1968) surveyed 60 citrus
growers in Renmark, Berri, Loxton, and Waikerie in South
Australia's Riverland district. He found that growers who were
well-off tended to admit that salinity had affected them, while
those who were obviously struggling tended to discount the
effects, and to refuse to admit that salinity was a serious
problem.

This research suggests one major and two minor hypotheses for
investigation in the South Australian situation:

Major Hypothesis 1: Because salinity is such a complex
and slowly developing phenomenon, both farmers and the general
public will have a very sketchy and distorted idea of the nature
of the problem and of the range of solutions available.

Minor Hypothesis 2: There will be a significant
difference in perception of the salinity problem among the
farmers, the general public, and the technical managers.

Minor Hypothesis 3: In accordance with the general
findings of a wide range of research into the perception of
hazards, farmers will be found to adopt a rationalizing stance in
the face of the threat from salinity, will discount the bad side
effects of any ameliorative measures tried, and will tend to rely
on the government for solutions.

The Investigation

The above hypotheses provide the framework for this
investigation. The study is aimed at gaining some insight into
the salinity problem as perceived by those most directly affected
by it. It is largely a study in environmental perception.

Methodology

The investigation was conducted by questionnaire surveys of
farmers from the Loxton Irrigation Area, Renmark Irrigation Area,
and the Murray Bridge/Mypolonga district (see Appendix 5.1). A
second questionnaire survey was administered to randomly selected
residents of Adelaide (see Appendix 5.2). Finally, open-ended
interviews were conducted with official resource managers both in
the local districts and also in Adelaide.

COMPOSITION OF THE SAMPLE

In the Murray Bridge/Mypolonga district 27 farmers were
selected by the use of block numbers and a table of random
numbers. This sample represents more than 50 per cent of farmers
in the district (Table 5.1).

TABLE 5.1. Murray Bridge/Mypolonga Sample Characteristics

N

Size:

Less than 1 ha

4

1-5 ha

6

6-10 ha

3

11-15 ha

2

16-20 ha

3

21-25 ha

2

26-30 ha

4

31 -35 ha

1

36-40 ha

2

N

Land Use:

Citrus/stone fruit

10

Market gardening

6

Pasture

5

Pasture/oats

2

Pasture/vegetables

3

Citrus/vegetables

1

In the Loxton district 37 irrigation farmers were selected by the
use of block numbers and a table of random numbers. This sample
represents more than 10 per cent of blockers in the district
(Table 5.2).

TABLE 5.2. Loxton Sample Characteristics

Size:

N

1-5 ha

6-10 ha

16

11-15ha

11

16-20 ha

6

21 -25 ha

1

30-50 ha

3

N

Land Use:

Citrus/vines

15

Citrus/stone fruit

10

Citrus/stone fruit

5

Vines

4

Vines/stone fruit

2

Citrus

1

In the Renmark district 64 irrigation farmers were selected by
the use of block numbers and a table of random numbers. This
sample represents more than 15 per cent of blockers in the
district (Table 5.3).